I need help solving 400-20x=700-40x

Answer 1

Good Evening, Elly,

So, let's look at this equation:

400 - 20x = 700 - 40x

Some things to remember when solving equations:

(1) What you do to one side you must do to the other.

(2) You want to keep numbers or terms positive if possible.

So:

400 - 20x = 700 - 40x

400 + 20x = 700 <-------Add 20x to both sides

20x = 300 <-------Subtract 400 from both sides

x = 15

Now, let's check our equation and work, okay?

400 - 20x = 700 - 40x

400 - 20(15) = 700 - 40(15)

400 - 300 = 700 - 600

100 = 100

Yes, the solution checks out and is valid. I hope I have assisted you and wish you a great ending to your week. If you have any feedback, or questions regarding this solution, please feel free to leave it or them in the comment section under this solution. If you need further assistance, please feel free to reach out to me or any tutor. Best!

Answer 2

You need to get x by itself on one side of the equation.

400 - 20x = 700 - 40x

Add 40x to both sides and get

400 + 20x = 700

Subtract 400 from both sides and get

20x = 300

Divide both sides by 20 and get

x = 300/20 = ?

Test the answer.

Answer 3

400 - 20x = 700 - 40x

-20x + 40x = 700 - 400

20x = 300

x = 15